Most of the conventional generator systems use the piston type engines utilizing fuel as the power source. The engine utilizing the fuel as the power source would discharge gas with many harmful substances to pollute the environment because of insufficient fuel combustion on one hand, and on the other hand, the fuel is extracted from petroleum, and the development and utilization of the system using the fuel engine as the power source are increasingly limited by the increasing lack of the petroleum source. So an impending problem is to develop new, clean and pollution-free alternative energy sources or decrease the fuel consumption and the emissions as far as possible. Therefore, many intricate and hard efforts are made in various countries, and many power sources such as alternative fuels, electro-drive, fuel cells and solar cells etc are studied and developed. But the new power sources or the hybrid power sources constructed thereof also have many disadvantages, so a new type of pollution-free and inexhaustible power source is needed, and the compressed air power source meets the need fitly.
An engine operating at fuel supply mode and compressed air supply mode is disclosed in FR2731472A1. The engine uses common fuel such as gasoline or kerosene on the highways, and when slow moving in the urban and the suburb, the compressed air (or other pollution-free compressed gas) is injected in the combustion chamber. The engine can decrease the fuel consumption partially, but the emission problem isn't solved because of utilizing the operating mode of fuel.
In order to further decrease pollution, a net air-powered engine is disclosed in U.S. Pat. No. 6,311,486 B1. This type of engine utilizes three independent chambers: an intake-compression chamber, an expansion and discharge chamber, and a constant volume combustion chamber. The intake-compression chamber is connected with the constant volume combustion chamber by a valve, and the constant volume combustion chamber is connected with the expansion and discharge chamber by a valve. One question of the engine is that the compressed air takes a long time to travel from the intake-compression chamber to the expansion and discharge chamber, so it takes a long time to obtain the power source gas for driving the piston to do work. At the same time, the high pressure gas discharged from the expansion and discharge chamber is not used, so the operation efficiency and the continuous working period for one charge of the engine are limited.
An air-powered engine assembly used in a vehicle is disclosed in a patent document CN101413403A (the family PCT application is WO2010051668A1) of the present applicant. The engine includes a gas tank, an air distributor, an engine, a linkage device, a clutch, an automatic transmission a differential mechanism and an impeller generator placed in the discharge chamber. The engine utilizes the compressed air to do work without any fuel, so no exhaust gas is discharged, and the “zero emission” is achieved. The exhaust gas is used repeatedly to generate electricity, so it can save the energy source and reduce the cost. But the engine is based on the traditional four-stroke engine, and when the crankshaft rotates through 720 degrees, the piston does work once. The high pressure air used as the power source can push the piston to do work when entering the cylinder, and then discharge, i.e., the strokes of the compressed air engine are an intake-expansion stroke and a discharge stroke actually. Obviously, the four-stroke engine disclosed in the patent document CN101413403A greatly wastes the effective working stroke, and the efficiency of the engine is limited. And the end gas of the engine can't be cycled and utilized well, and it needs a large enough gas tank to store the high pressure air for working a long time, so the applied prospect of the compressed air engine in the industry is degraded.
The air-powered engines mentioned above are based on when the pistons move at the bottom dead point in the cylinders, the pistons are driven by the flywheels and continue to move from the bottom dead point to the top dead point by the inertia of the crankshaft movement, so the compressed air in the working chambers is discharged. However, because the compressed air has high pressure after expanding for pushing the pistons to do work in the working chamber, and the compressed air under a pressure is discharged by the pistons by means of the rotary inertia of the crankshafts and the flywheels, it seems “lack power”, and the condition appears notably when the engine rotates with low speed. In order to improve the rotary speed of the air-powered engine as far as possible, the pistons are needed to move more quickly in the working chamber. And in order to improve the stable torque output at a low rotary speed of the air-powered engine, an auxiliary power unit is needed for the crankshaft.
Now, the common auxiliary power unit is an electromagnetic or permanent magnetic auxiliary power unit. Chinese patent document CN2512700Y disclosed an electromagnetic auxiliary power unit for a bicycle which assists rotation of a wheel by means of the interaction of a magnet and an electromagnet, so double effects of saving energy and auxiliary power are realized. Another patent document WO2004009424A1 disclosed an electric powered steering gear using an electromagnetic coil to relieve the fatigue of a driver. So the auxiliary power unit using an electromagnet or a permanent magnet as a movable part is put in practice in many industries.
An object of the invention is to provide a generator system using a compressed air-powered engine as the power source, so the application of the compressed air can be realized in industrial power generation. And the air-powered engine system disclosed in the present application includes an electromagnetic auxiliary power unit for the crankshaft auxiliary power. So it provides the rotary auxiliary power for the crankshaft of the engine, and thus improves the rapid rotary performance of the air-powered engine and the stable torque output at low rotary speed, and then increases the efficiency of the air-powered engine.